This part is a kind of semiconductor called K4078.

Function of this product has 2SK4078.

Manufacturers : NEC

Image and pinout :

Some of the text within the PDF file :

DATA SHEET MOS FIELD EFFECT TRANSISTOR 2SK4078 SWITCHING N-CHANNEL POWER MOS FET DESCRIPTION The 2SK4078 is N-channel MOS Field Effect Transistor designed for high current switching applications. ORDERING INFORMATION PART NUMBER LEAD PLATING 2SK4078-ZK-E1-AY Note 2SK4078-ZK-E2-AY Note Pure Sn (Tin) PACKING Tape 2500 p/reel Note Pb-free (This product does not contain Pb in external electrode.) PACKAGE TO-252 (MP-3ZK) typ. 0.27 g FEATURES • Low on-state resistance RDS(on)1 = 8.5 mΩ MAX. (VGS = 10 V, ID = 25 A) RDS(on)2 = 14.0 mΩ MAX. (VGS = 4.5 V, ID = 13 A) • Low input capacitance Ciss = 2300 pF TYP. • Logic level drive type (TO-252) ABSOLUTE MAXIMUM RATINGS (TA = 25°C) Drain to Source Voltage (VGS = 0 V) VDSS 40 Gate to Source Voltage (VDS = 0 [ ... ]

K4078 PDF Datasheet Download